It is common to rate compressed air consumption in Standard Cubic Feet per Minute – SCFM.
The SCFM – Standard Cubic Feet per Minute – determines the weight of air to fixed or “Standard” conditions. There are several definitions of SCFM. The most common used in the United States is with the “sea-level” properties:
- 14.696 Pounds per Square Inch (psia)
- 60 Degrees Fahrenheit ( oF) (520 o R)
- 0% Relative Humidity (RH)
Europeans normally use one ata and 0 oC as SCFM.
Note that the The Compressed Air & Gas Institute and PNEUROP have adopted the definition used in ISO standards with dry (0% relative humidity) air at 14.5 psia (1 bar) and 68 oF (20 oC).
(See also, ‘Flow of compressor output definitions’)